Ultraviolet light activated oxidation process for the reduction of organic carbon in semiconductor process water

Abstract

In a system for decomposing organic compounds in water for use in semiconductor manufacturing, a chemical reactor vessel having a fluid inlet and a fluid outlet, a persulfate anion addition system upstream of the reactor vessel, and a light emitting device contained within the reactor vessel. The light emitting device provides light capable of decomposing persulfate anions.

What is claimed as invention is: 
     
       1. A method of treating semiconductor manufacturing water to reduce total organic carbon (TOC), the method comprising:
 providing a source of semiconductor manufacturing water; 
 adding a solution of aqueous persulfate to the semiconductor manufacturing water to provide a mixture; 
 exposing the mixture to ultraviolet light in a chemical reactor vessel for a predetermined residence time to provide a treated water comprising a TOC concentration of less than about 5 ppb; 
 measuring the TOC concentration of at least one of the semiconductor manufacturing water and the treated water; and 
 adjusting a rate of aqueous persulfate addition to the semiconductor manufacturing water based on a TOC measurement of the at least one of the semiconductor manufacturing water and the treated water. 
 
     
     
       2. The method of  claim 1 , wherein the treated water comprises a TOC concentration of less than about 1 ppb. 
     
     
       3. The method of  claim 2 , wherein adjusting the rate of aqueous persulfate addition is based on a TOC measurement of the semiconductor manufacturing water. 
     
     
       4. The method of  claim 2 , further comprising removing dissolved solids and dissolved gases. 
     
     
       5. The method of  claim 2 , wherein adjusting the rate of aqueous persulfate addition is based on a TOC measurement of the treated water. 
     
     
       6. The method of  claim 1 , wherein exposing the mixture to ultraviolet light in a chemical reactor vessel comprises exposing the mixture to ultraviolet light in a plug-flow reactor. 
     
     
       7. The method of  claim 1 , wherein exposing the mixture to ultraviolet light in a chemical reactor vessel comprises exposing the mixture to ultraviolet light in a continuous-stirred tank reactor. 
     
     
       8. The method of  claim 7 , wherein exposing the mixture to ultraviolet light in a chemical reactor vessel comprises exposing the mixture to ultraviolet light in a plug-flow reactor downstream of the continuous-stirred tank reactor. 
     
     
       9. The method of  claim 1 , further comprising passing the semiconductor manufacturing water through a reverse osmosis unit prior to adding a solution of persulfate to the semiconductor manufacturing water. 
     
     
       10. The method of  claim 1 , wherein the method is performed at ambient temperature.